The Navi Mumbai Municipal Corporation (NMMC) has ordered 19 construction sites to halt work and issued notices to 42 others for violating air pollution control norms. This action is part of the enforcement of GRAP-4 measures, with work stopped at locations where the Air Quality Index (AQI) exceeded 200. NMMC has also issued penalty notices to 173 developers for non-compliance with 27-point pollution control guidelines, which include mandatory air quality monitoring equipment installation. Officials attribute rising pollution to winter conditions and urge reliance on official AQI data sources.